Dockerfile for rails api with alpine image

Dockerfile

FROM ruby:2.4.1-alpine
RUN set -x \
  && apk upgrade --no-cache \ 
  && apk add --no-cache --virtual build-dependencies \
    build-base libc-dev linux-headers tzdata \
    openssl-dev postgresql-dev \
  && apk add --no-cache \
    libxml2-dev \
    libxslt-dev \
  && gem install nokogiri \
    -- --use-system-libraries \
    --with-xml2-config=/usr/bin/xml2-config \
    --with-xslt-config=/usr/bin/xslt-config

RUN mkdir /app_name_api
WORKDIR /app_name_api
ADD Gemfile /app_name_api/Gemfile
ADD Gemfile.lock /app_name_api/Gemfile.lock
RUN bundle install
ADD . /app_name_api